1. Field of the Invention
The present invention relates to IC sockets.
2. Description of the Related Art
There has been proposed an IC socket having a plurality of contact pins for connection with the terminals of a semiconductor package to test the electrical characteristics of the semiconductor package.
FIG. 2 shows a first example of a conventional IC socket with a contact pin in contact with the terminal of a semiconductor package. FIG. 3 shows the contact pin of a second conventional IC socket in contact with the terminal of a semiconductor package.
In FIG. 2, a semiconductor package 51 has a plurality of terminals 52. An IC socket body 53 has the corresponding number of metal contact pins 54 to the number of the terminals 52. Each contact pin 54 is provided at a position corresponding to the position of each terminal 52 such that the contact portion 57 is brought into contact with the terminal 52 for connection to measuring equipment (not shown). A pressure member 55 is pressed downwardly by a pressing device (not shown) so as to press the terminal 52 against the contact portion 57. The contact pin 54 has a substantially U-shaped form to provide flexibility and is provided in a groove 56 of the socket body 53 so that the contact portion 57 is flexible downwardly.
Where a large amount of solder or dust particles (hereinafter xe2x80x9csolderxe2x80x9d) is adhered to the back side of the terminal 52, the electrical contact between the terminal 52 and the contact pin 54 becomes so poor that it becomes defective. The dust particles are usually wastes of mold resins and fillers. An excessive amount of solder applied to the terminal 52 also causes poor contact. If there is a poor contact between the backside of the terminal 52 and the contact portion 57 of the contact pin 54, it is impossible to conduct appropriate test of the electrical characteristics of a semiconductor package.
Consequently, the contact portion 57 is provided with a first contact face 57a and a second contact face 57b so that when the terminal 52 is pressed against the contact pin 54, the first contact face 57a slides on the back side of the terminal 52 to wipe out the xe2x80x9csolderxe2x80x9d from the back side and then the second contact face 57b makes contact with the wiped and cleaned backside of the terminal 52. This makes a good electrical contact between the backside of the terminal 52 and the contact portion 57 of the contact pin 54.
In FIG. 3, the contact portion 57 of the contact pin 54 is provided with a plurality of triangular projections, forming a saw tooth configuration.
Similarly to the first example, when the terminal 52 is pressed against the contact portion 57 of the contact pin 54, the projections of the contact portion 57 wipe the backside of the terminal 52 to remove the xe2x80x9csolderxe2x80x9d from the backside so that the tips of the projections are brought into contact with the cleaned backside of the terminal 52. This makes a good electrical contact between the backside of the terminal 52 and the contact portion 57 of the contact pin 54. In addition, the xe2x80x9csolderxe2x80x9d removed from the backside is kept as remains 59 between the projections.
In the above IC sockets, however, the entire backside of the terminal 52 is wiped so that a large amount of xe2x80x9csolderxe2x80x9d is removed and scattered, contaminating the surrounding atmosphere. In the above second example, the xe2x80x9csolderxe2x80x9d is kept between the projections as remains 59 so that when the amount of the remains 59 becomes large, the remains 59 fall out and spread to contaminate the surrounding atmosphere.
If the surrounding atmosphere is contaminated, unexpected short-circuitry, etc. occurs, making it impossible to test the electrical characteristics of the semiconductor package. In addition, if the semiconductor package or manufacturing equipment is contaminated, the manufactured semiconductor package becomes defective, reducing the throughput or yield of the semiconductor manufacturing process.
If a large amount of xe2x80x9csolderxe2x80x9d accumulate on the contact portion 57 of the contact pin 54, the electrical contact between the backside of the terminal 52 and the contact portion 57 of the contact pin 54 is blocked. If the force to press the terminal 52 against the contact pin 54 is reduced so as to control the amount of xe2x80x9csolderxe2x80x9d removed by wiping, the contact pressure between the backside of the terminal 52 and the contact portion 57 of the contact pin 54 becomes too low to provide good contact. Where the xe2x80x9csolderxe2x80x9d adhered to the backside of the terminal 52 is waste of the mold resin or filler, the adhering power is so high that the waste is not removed by wiping. Consequently, the electrical contact between the backside of the terminal 52 and the contact portion 57 of the contact pin 54 is blocked.
Accordingly, it is an object of the invention to provide an IC socket capable of removing a small amount of xe2x80x9csolderxe2x80x9d without contaminating the surrounding atmosphere and eliminating poor contacts caused by an unsatisfactory contact pressure between the backside of the terminal 52 and the contact portion 57 of the contact pin 54 or remains of xe2x80x9csolderxe2x80x9d adhered to the backside of the terminal 52, thus making it possible to conduct appropriate test of the electrical characteristics of a semiconductor package.
According to the invention there is provided an IC socket which comprises a socket body and a contact pin with a contact face supported by the socket body such that it is flexible toward the inside of the socket body. The contact face is made by rounding an upper rectangular portion of the contact pin for contact with the terminal of a semiconductor package.